Residual toner removing apparatus

ABSTRACT

A residual toner removing apparatus which comprises a cleaner section, a dust collecting section, a filter section and a suction section contained in a housing having an opening adjacent to a known photoreceptor surface. Brush bristles of a cleaner brush cylinder in the cleaner section are adapted to be charged with the same polarity as toner particles wiped off the photoreceptor surface so as to repel the toner particles, which are subsequently fed by an air flow into the dust collecting section and attracted by dust collecting plates with opposite charge for accumulation in the dust collecting section. The toner particles still remaining in the air flow are filtered in the filter section with a coarse filter and a fine rollup filter for complete elimination.

Tanaka et al.

[ Oct. 7, 1975 RESIDUAL TONER REMOVING APPARATUS [75] Inventors: SusumuTanaka, Sakai; Hidetoshi Kawabata, Tondabayashi; Yuji Enoguchi,Higashiosaka, all of Japan [73] Assignee: Minolta Camera KabushikiKaisha,

Japan 221 Filed: Jan. 24, 1974 21 Appl. No.: 436,373

30 Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS1,052,019 12/1966 United Kingdom l5/1.5

OTHER PUBLICATIONS IBM Technical Disclosure Bulletin, Vol. 15, No. 12,May 1973, p. 3643.

Primary ExaminerDaniel Blum Attorney, Agent, or Firm-Wenderoth, Lind &Ponack [5 7] ABSTRACT A residual toner removing apparatus whichcomprises a cleaner section, a dust collecting section, a filter sectionand a suction section contained in a housing having an opening adjacentto a known photoreceptor surface. Brush bristles of a cleaner brushcylinder in the cleaner section are adapted to be charged with the samepolarity as toner particles wiped off the photoreceptor surface so as torepel the toner particles, which are subsequently fed by an air flowinto the dust collecting section and attracted by dust collecting plateswith opposite charge for accumulation in the dust collecting section.The toner particles still remaining in the air flow are filtered in thefilter section with a coarse filter and a fine rollup filter forcomplete elimination.

7 Claims, 3 Drawing Figures U.S. Patent Oct. 7,1975

FIG. 3

RESIDUAL TONER REMOVING APPARATUS The present invention relates to atoner removing apparatus and, more particularly, to a residual tonerremoving apparatus for an electrostatic copying machine.

According to a conventional residual toner removing apparatus, theelimination of toner particles remaining on a photoreceptor surfaceafter transferring a toner powder image on a copy paper sheet is carriedout by wiping the residual toner particles off the photoreceptor surfacewith a rotating cleaner brush after the photoreceptor is electricallyneutralized by an AC. discharger. Although the residual toner particlesmay be approximately completely removed from the photoreceptor surfaceby the above procedure alone, the toner particles adhering to the brushbristles of the cleaner brush can not be sufficiently collected by amere suc- ,tion device such as fan, the amount of toner particlesadhering to the bristles gradually increasing in the course of time withreduction of cleaning effect and durability of the cleaner brush itself,resulting in a larger power consumption during operation of theapparatus.

In the conventional residual toner removing device of the aboveconstruction, a filter of filter bag type is employed which, besidesbeing bulky and troublesome in replacing is not sufficiently efficientfor perfectly filtering the small amount of toner particles contained ina cleaning air flow, resulting in a larger size of the apparatus itself.

Accordingly, an essential object of the present invention is to providea compact residual toner removing apparatus which provides efficientremoval of residual toner particles with subsequent elimination of thedisadvantages inherent in the conventional residual toner removingdevice.

Another important object of the present invention is to provide theresidual toner removing apparatus of the above described type whereinbrush bristles of a cleaner brush are electrically charged with the samepolarity as the toner particles for easy removal of the toner particlesfrom the brush bristles.

A further object of the present invention is to provide the residualtoner removing apparatus of the above described type wherein thecollection of removed toner particles are easily effected by theprovision of a removable cover plate having dust collecting plateselectrically charged with opposite polarity to the toner particles, anda buffer plate for an air flow containing toner particles.

A still further object of the present invention is to provide theresidual toner removing apparatus of the above described type whereinthe toner particles contained in the air flow are Completely filtered ata coarse filter and a fine filter without clogging the filters andvariation in the rate of air flow.

According to the preferred embodiments of the present invention, theresidual toner removing apparatus comprises a cleaner section, a dustcollecting section, a filter section and a suction section contained ina housing having an opening adjacent to a known photoreceptor surfacedriven by a conventional means. In the cleaner section close to thephotoreceptor surface, a cleaner brush cylinder with brush bristlessecured to the surface thereof is adapted to rotate between an uppercasing plate and a lower casing electrically insulated from each other,the brush bristles rubbing during rotation against the middle portion ofthe upper casing,

thus being charged with the same positive polarity as toner particles,so that the toner particles wiped off the photoreceptor surface by thebrush bristles are electrically repelled from the bristles and fed intosubsequent sections by an air flow through a space between the tips ofthe bristles and the lower casing for complete elimination of residualtoner particles from the photoreceptor surface and the cleaner brush.

Furthermore, the above upper casing plate with negative charge iselectrically connected to a pair of dust collecting plates in the dustcollecting section for positively attracting the removed toner particlesthereto. The subsequent filter section comprises a coarse filter, and afine rollup filter with filter screen successively displaceable bywinding, thus resulting in small size of the whole apparatus withuniform air flow and suction force by the suction section for perfectelimination of residual toner particles.

These and other objects and features of the present invention willbecome apparent from the following description taken in conjunction withthe preferred embodiment thereof with reference to the accompanyingdrawings, in which;

FIG. 1 is a schematic diagram showing a sectional side view of aresidual toner removing apparatus according to the present invention,

FIG. 2 is a schematic diagram showing a perspective view of afilter'section of the above residual toner removing apparatus, and

FIG. 3 is a cross sectional view taken along the line IIII in FIG. 1.

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like numerals throughout theviews of the accompanying drawings.

Referring to FIG. 1, the residual toner removing apparatus which extendsthe width of a known electrophotosensitive photoreceptor l of anelectrostatic copying machine generally comprises 4 sections, i.e., acleaner section A, a dust collecting section B, a filter section C andsuction section D contained in a housing T of rectangular prism shapehaving an elongated opening Ta extending the width of the photoreceptor1 adjacent to the surface thereof. The photoreceptor l is of a knownconstruction and driven by a conventional means.

In the cleaner section A, the bottom of the housing T close to theopening Ta is formed into a concave lower casing 5 in the form of atrough, over which a cleaner brush cylinder 2 with-brush bristles 3 ofanimal fur such as rabbit fur or synthetic fur secured to the surfacethereof is rotatably provided by suitable means. A

convex upper casing plate 4 fixedly provided above the brush cylinder 2is electrically insulated from the lower casing 5, and divides thecleaner section A into two portions, A for the cylinder 2 and 7 for airpassage. The tips of the brush bristles 3 are adapted to rub against theinner surface of the upper casing plate 4 of the middle part 4a thereof,keeping a fixed distance 6 to the inner surface of the lower casing 5during rotation, while applying very light pressure to the photoreceptorsurface 1. The upper casing 4 which extends the width of the housing Tis made of brass, being adapted to be charged negative when rubbed bythe tips. of brush bristles 3 during rotation of the cylinder 2, whilethe brush bristles 3 are charged positive, i.e., the same polarity asthe toner powder.

The dust collecting section B further comprises a removable rectangularcover plate 9 which fits a rectangular opening Tb formed in the bottomof the housing T and extends the width of the housing T, two dustcollecting plates 10 and 10' removably fixed on the cover plate 9 atright angles thereto in spaced relation to each other, projectingapproximately half way into the housing T, and a buffer plate 11 fixedat right angles to the inner surface of the housing T at the upper partthereof and projecting half way into the housing T between the plates 10and 10, the dust collecting plates 10 and 10' and the buffer plate 1 1extending the width of the housing T forming a passage 12 for air flowcontaining toner particles. The plates 10 and 10' are electricallyconnected to the upper casing 4 with negative charge in the cleanersection A. Accordingly, the residual toner particles with positiveCharge wiped off the surface of the photoreceptor 1 by the rotation ofthe brush bristles 3 and contained in the flow of air caused by asilocco fan 17 provided in the suction section D are adapted to beattracted to the surfaces of the dust collecting plates 10 and 10 withnegative charge.

Referring to FIG. 2, the filter section comprises a coarse filter 13installed adjacent to the plate 10 with a fine rollup filter 14 providedat the back of the filter 13 in spaced relation, the rollup filter 14being adapted to be successively wound into a case 15 by turning awinding knob 16 as in a camera. The filters 13 and 14 are of suchdimensions that fit the width and the height of the housing T, forming afilter partition in the housing T at the back of the plate 10. In thesuction section D at the other end of the housing T remote from the sidethereof facing the photoreceptor l, the sirocco fan 17 for suction isprovided to cause the air flow through the housing T.

Referring back to FIG. 1, when the cleaner brush cylinder 2 is rotatedin the opposite direction to the photoreceptor 1 as is shown by anarrow, for example, at a in the opposite polarity to the tonerparticles. In the above state, since the residual toner particles andthe brush bristles 3 charged with the same positive polarity repel eachother, the toner particles are separated from the brush bristles 3 bythe centrifugal force and the air flow caused by the above mentionedsirocco fan 17, thus being fed into the dust collecting section Bthrough the space 6 between the bristles 3 and the lower casing 5. Asthe bristles 3 closely contact the middle portion 4a of the upper casing4, the separated toner particles are not normally pushed out onto thephotoreceptor 1 at the upper part between the photoreceptor 1 and theopening Ta during rotation of the It should be noted here that the dustcollecting plates 10 and 10' are made of electrically conductingmaterial such as aluminum are connected to the upper casing 4 by a lineL as is seen from FIG. 1 and adapted to be: charged with a voltagebetween 4000 and 5000 volts in the opposite polarity to the tonerparticles similarly to the upper casing 4, while the lower casing 5 iselectrically insulated from the dust-collecting electrode plates 10 and10' and also earthed through a lineL.

The provision of thebaffle plate 11 between the plates 10 and 10 iseffective for preventing the air flow containing the separated tonerparticles from being directly fed into the filter section C withsufficient attraction of the toner particles to the surfaces of theplates,

10 and 10, and also for efficiently dropping the toner particles on thecover plate 9 by gravity. Referring to FIG. 3, which shows a mechanismfor removing the toner particles adhering to the surface of spectively.A knob 19 is'rigidly fixed'to'the right end of I the bar 18 projectingfrom the opening Tc while a rectangular electode cleaner plate 20contacting the left' side wall of the housingT is secured tothe left endof the bar 18 inside the housing T. The cleaner plate 20 with heightfitting in the height of the side walls of the housing'T and lengthextending the length of the dust collecting section Bis provided withslits corresponding to the cross sections of the dust collecting plates10 and 10 and also the buffer platell, so thatthe' plate 20 can beslidably moved along the surfaces of the plates 10 and 10, and thebaffle plate 11 inclose contact therewith. A band of blade 21 made ofelastic mate rial such as rubber and having the fa-cross section of aright- ,angled triangle is rigidly fixedto the surface of the cleanerplate 20 along the configuration of the slits" thereon for a firmcontact without rattling orthe like. An outlet T d for the toner powderextending the flenght of the cleaner plate 20 is provided at the lowerpart of the right side wall of the housing T with a correspondingtrough-shape toner tank 22 removably attached to the edges of the outletTd. For removing the'toner particles adhering to the surfaces of theplates 10 and 10,

and the baffle plate 11, the knob 19 is pulled out in the direction ofan arrow to the position shown in chain lines with the cleaner plate 20and the blade 21 moving in the same direction by means of the guide bar18, during which time the blade '21 scrapes theitoner powder off thesurface of the plates 10 and 10" and the baffle plate 11, simultaneouslycarrying'the-removed toner brush cylinder 2. Should the toner particlescome out onto the photoreceptor l at the upper part thereof, they arecarried into the dust collecting section B by an air flow shown with anarrow through the passage 7 formed between the upper casing 4 and thetop of the housing T without scattering onto the photoreceptor side.

The positively charged toner particles thus fed into the dust collectingsection B are attracted by the negatively charged dust collecting plates10 and 10 which are electrically connected to the upper casing 4 alsoFurthermore, as the fine rollup filter .14 can be successively displacedby winding in the direction of the arrow in FIG. 2 so as to bringunexposed filter screen into the path of the incoming air, no reductionof air flow rate is caused by the clogging of the filter screen.

Although, in the above embodiment, the positively charged residual tonerparticles on the photoreceptor 1 are wiped off by the brush bristles 3of the brush cylinder 2, electrically repelled from the positivelycharged brush bristles 3, and fed into the dust collecting section B bythe air flow, provision of a flicker rod 8 at the rear of the brushcylinder 2 in the path of the brush bristles 3 for mechanically beatingoff negatively or neutrally charged toner particles without electricalrepelling is effective for more complete elimination of the tonerparticles as adhesion of the toner particles to the brush bristles 3 isfurther prevented. In this case,

the flicker rod 8 is of a conventional construction.

From the foregoing description, it has now become clear that, accordingto the first embodiment of the present invention, the residual tonerparticles adhering to the photoreceptor surface 1 are mechanically wipedoff by the brush bristles 3, and the toner particles separated therebywith positive charge are electrically repelled by the positively chargedbrush bristles 3, simultaneously being carried away into the dustcollecting section B by the air flow, thus keeping the photoreceptorsurface 1 perfectly clean for a long period of time with effectivecollection of the separated toner.

In the second embodiment according to the present invention, in additionto the above described effect, the dust collecting plates 10 and 10 areelectrically connected to the upper casing 4 for charging the plates 10and 10' with opposite polarity to the separated toner powder as thebrush bristles 3 rub against the middle portion 4a of the upper casing 4during rotation, thus completely eliminating the toner particlescontained in the air flow by electrical attraction.

Furthermore, the provision of the buffer plate 11 to divert the air flowis effective for more efficient collection of the separated tonerparticles by gravitation. The removable cover plate 9 having the dustcollecting plates 10 and 10' removably secured thereon is convenient foreasy collection of the removed toner powder.

In the third embodiment according to the present invention, the smallsized filter comprising the coarse filter 13 and fine rollup filter 14adopted instead of the conventional bulky filter of filter bag typeefficiently prevents the clogging of filter screen with constant flowrate of air especially by the fine rollup filter 14 being successivelydisplaceable by winding.

Accordingly, in the residual toner removing apparatus according to thepresent invention, the residual toner particles wiped off thephotoreceptor surface by the brush bristles during rotation of the brushcylinder are positively fed into the subsequent sections without thetoner particles being dispersed outside the apparatus and with minimumsoiling of the brush bristles, thus the photoreceptor surface beingthoroughly cleaned with little power consumption, which is suitable forwide industrial application.

Although the present invention has been fully described by way ofexample with reference to the attached drawings, it is to be noted thatvarious changes and modifications are apparent to those skilled in theart. Therefore, unless otherwise such changes and modifications departfrom the scope of the present invention, they should be construed asincluded therein.

What is claimed is:

1. In a residual toner removing apparatus which comprises a cleanersection, a dust collection section, and a filter section followed by asuction section, the improvements which comprise brush bristles of acleaner brush cylinder rotatably provided in said cleaner section beingadapted to rub against an upper casing plate at an approximately middleportion thereof for charging said brush bristles with the same polarityas toner particles, and said upper casing plate with opposite polarityto said brush bristles, and said cleaner brush cylinder being providedbetween said upper casing plate and a lower casing electricallyinsulated from each other with a fixed distance between tips of saidbrush bristles and said lower casing, said toner particles wiped off aphotoreceptor surface by said brush bristles being electrically repelledfrom said brush bristles and simultaneously fed into a subsequent dustcollecting section by an air flow produced by a suction in said suc'tion section, and dust collecting plates provided in said dustcollecting section, said dust collecting plates being electricallyconnected to said charged upper casing plate for attracting said tonerparticles to said dust collecting plates.

2. In a residual toner removing apparatus which comprises a cleanersection, a dust collecting section, and a filter section followed by asuction section, the improvements which comprise brush bristles of acleaner brush cylinder rotatably provided in said cleaner section beingadapted to rub against an upper casing plate at an approximately middleportion thereof for charging said brush bristles with same polarity astoner particles and said upper casing plate with opposite polarity tosaid brush bristles, and said cleaner brush cylinder being providedbetween said upper casing plate and a lower casing electricallyinsulated from each other with a fixed distance between tips of saidbrush bristles and said lower casing, said toner particles wiped off aphotoreceptor surface by said brush bristles being electrically repelledfrom said brush bristles and simultaneously fed into a subsequent dustcollecting section by an air flow produced by a suction in said suctionsection, wherein a coarse filter and a fine rollup filter with filterscreen successively displaceable by winding are provided in said filtersection between said dust collecting section and said suction section,said coarse filter being positioned to the side of said dust collectingsection.

3. In a residual toner removing apparatus which comprises a cleanersection, a dust collecting section, and a filter section followed by asuction section, the improvements which comprise brush bristles of acleaner brush cylinder rotatably provided in said cleaner section beingadapted to rub against an upper casing plate at an approximately middleportion thereof for charging said brush bristles with same polarity astoner particles and said upper casing plate with opposite polarity tosaid brush bristles, for preventing the toner particles from adhering tosaid brush bristles and said cleaner brush cylinder being providedbetween said upper casing plate and a lower casing electricallyinsulated from each other with a fixed distance between tips of saidbrush bristles and said lower casing, said toner particles wiped off aphotoreceptor surface by said brush bristles being electrically repelledfrom said brush bristles and simultaneously fed into a subsequent dustcollecting section by an air flow produced by a suction in said suctionsection, said cleaner brush, after the brush bristles thereof rubagainst said upper casing, rotating in a direction to move along saidlower casing with a small gap maintained between said brush bristles andsaid lower casing, said upper casing and an upper part of a housing ofsaid residual toner removing apparatus defining, at edges thereofadjacent to said photoreceptor surface, an air suction inlet with saidupper casing and said upper part of said housing being disposed at apredetermined distance from each other for forming an air passagetherebetween, a flicker means being disposed at a side of said cleanerbrush whereat said cleaner section communicates with said suctionsection, and in such a position that said flicker means strikes againstsaid brush bristles as said cleaner brush rotates.

4. A residual toner removing apparatus as claimed in claim 3 whereinsaid flicker means is a flicker bar disposedat a central portion of anair outlet defined by the edge of said upper casing remote from saidphotoreceptor surface and said lower casing.

5. A residual toner removing apparatus as claimed in claim 1, furthercomprising a baffle plate provided between said dust collecting plates.

6. A residual toner removing apparatus as claimed in claim 1 wherein acleaner plate having slits corresponding to cross sections of said dustcollecting plates and said baffle plate is provided in said dustcollecting section so as to move along surfaces of said dust collectingplates and baffle plate.

7. A residual toner removing apparatus as claimed in claim 4, wherein ablade is rigidly fixed to a surface of said cleaner plate alongconfiguration of said slits for better contact between slits of saidcleaner plate and said dust collecting plates and said baffle plate.

1. In a residual toner removing apparatus which comprises a cleanersection, a dust collection section, and a filter section followed by asuction section, the improvements which comprise brush bristles of acleaner brush cylinder rotatably provided in said cleaner section beingadapted to rub against an upper casing plate at an approximately middleportion thereof for charging said brush bristles with the same polarityas toner particles, and said upper casing plate with opposite polarityto said brush bristles, and said cleaner brush cylinder being providedbetween said upper casing plate and a lower casing electricallyinsulateD from each other with a fixed distance between tips of saidbrush bristles and said lower casing, said toner particles wiped off aphotoreceptor surface by said brush bristles being electrically repelledfrom said brush bristles and simultaneously fed into a subsequent dustcollecting section by an air flow produced by a suction in said suctionsection, and dust collecting plates provided in said dust collectingsection, said dust collecting plates being electrically connected tosaid charged upper casing plate for attracting said toner particles tosaid dust collecting plates.
 2. In a residual toner removing apparatuswhich comprises a cleaner section, a dust collecting section, and afilter section followed by a suction section, the improvements whichcomprise brush bristles of a cleaner brush cylinder rotatably providedin said cleaner section being adapted to rub against an upper casingplate at an approximately middle portion thereof for charging said brushbristles with same polarity as toner particles and said upper casingplate with opposite polarity to said brush bristles, and said cleanerbrush cylinder being provided between said upper casing plate and alower casing electrically insulated from each other with a fixeddistance between tips of said brush bristles and said lower casing, saidtoner particles wiped off a photoreceptor surface by said brush bristlesbeing electrically repelled from said brush bristles and simultaneouslyfed into a subsequent dust collecting section by an air flow produced bya suction in said suction section, wherein a coarse filter and a finerollup filter with filter screen successively displaceable by windingare provided in said filter section between said dust collecting sectionand said suction section, said coarse filter being positioned to theside of said dust collecting section.
 3. In a residual toner removingapparatus which comprises a cleaner section, a dust collecting section,and a filter section followed by a suction section, the improvementswhich comprise brush bristles of a cleaner brush cylinder rotatablyprovided in said cleaner section being adapted to rub against an uppercasing plate at an approximately middle portion thereof for chargingsaid brush bristles with same polarity as toner particles and said uppercasing plate with opposite polarity to said brush bristles, forpreventing the toner particles from adhering to said brush bristles andsaid cleaner brush cylinder being provided between said upper casingplate and a lower casing electrically insulated from each other with afixed distance between tips of said brush bristles and said lowercasing, said toner particles wiped off a photoreceptor surface by saidbrush bristles being electrically repelled from said brush bristles andsimultaneously fed into a subsequent dust collecting section by an airflow produced by a suction in said suction section, said cleaner brush,after the brush bristles thereof rub against said upper casing, rotatingin a direction to move along said lower casing with a small gapmaintained between said brush bristles and said lower casing, said uppercasing and an upper part of a housing of said residual toner removingapparatus defining, at edges thereof adjacent to said photoreceptorsurface, an air suction inlet with said upper casing and said upper partof said housing being disposed at a predetermined distance from eachother for forming an air passage therebetween, a flicker means beingdisposed at a side of said cleaner brush whereat said cleaner sectioncommunicates with said suction section, and in such a position that saidflicker means strikes against said brush bristles as said cleaner brushrotates.
 4. A residual toner removing apparatus as claimed in claim 3wherein said flicker means is a flicker bar disposed at a centralportion of an air outlet defined by the edge of said upper casing remotefrom said photoreceptor surface and said lower casing.
 5. A residualtoner removing apparatus as claimed in claIm 1, further comprising abaffle plate provided between said dust collecting plates.
 6. A residualtoner removing apparatus as claimed in claim 1 wherein a cleaner platehaving slits corresponding to cross sections of said dust collectingplates and said baffle plate is provided in said dust collecting sectionso as to move along surfaces of said dust collecting plates and baffleplate.
 7. A residual toner removing apparatus as claimed in claim 4,wherein a blade is rigidly fixed to a surface of said cleaner platealong configuration of said slits for better contact between slits ofsaid cleaner plate and said dust collecting plates and said baffleplate.